Expand > Structure Results > Mass Summary > Mass Summary by Story . Improving Mass Accuracy ("Better" Mass)
The geometric center where the story mass is concentrated. Common Issues to Watch For Center of rigidity - ETABS - CSI Knowledge Base
To get the most accurate summary, you must first define the mass source correctly.
Have you ever noticed your base reactions don't match your mass? The Story Summary helps you pinpoint the culprit: etabs mass summary by story better
if your Dead Load pattern already includes a self-weight multiplier of 1.0. Include Imposed Loads : Per codes like
Compare total calculated mass against initial estimates in seconds. 2. Seamless Integration of Mass Sources
Confirm that "Lump Lateral Mass at Story Levels" is enabled to ensure masses are correctly aggregated at each floor for seismic analysis Coordinate System: Expand > Structure Results > Mass Summary >
: The absolute coordinates of the Center of Mass for that specific story.
Your hand-calculated weight using 1.0SW + 0.8SDL does not match the output in the Mass Summary by Story table. Cause: The "From Loads" option in your mass source applies loads to the entire structure on a tributary area basis. Shell elements are meshed to create analysis points (nodes). It's possible that your mass source is distributing the load perfectly, but the summary table is reporting the mass at the "story level" itself. Solution:
Ensure you are checking the "Include Lateral Mass" option for seismic analysis. Have you ever noticed your base reactions don't
Once the analysis is complete, the data is found in the Mass Summary by Story table.
To fully leverage the Story Mass Summary table, you must understand what its columns represent: The specific floor level defined in your story data.
What (e.g., ASCE 7, Eurocode 8) are you designing for? Are you using rigid or semi-rigid diaphragms?